Java 之c3p0连接池 + dbutils例子

一、代码

1、导入jar包

2、c3p0-config.xml

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>
    <default-config>
        <property name="jdbcUrl">jdbc:mysql://localhost:3306/tpexam?characterEncoding=utf-8&amp;useSSL=false</property>
        <property name="driverClass">com.mysql.jdbc.Driver</property>
        <property name="user">tpexam</property>
        <property name="password">123456</property>
        
        <!--  连接池参数  -->
        <!-- 超时时间 -->
        <property name="checkoutTimeout">30000</property>
        <property name="idleConnectionTestPeriod">30</property>
        <!-- 初始化申请的连接数量 -->
        <property name="initialPoolSize">5</property>
        <property name="maxIdleTime">30</property>
        <!-- 最大的连接数量 -->
        <property name="maxPoolSize">10</property>
        <property name="minPoolSize">1</property>
        <property name="maxStatements">200</property>
    </default-config>

</c3p0-config>

 3、具体代码

test.java

import java.sql.Connection;
import java.sql.SQLException;
import java.util.List;

import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;

import utils.DbUtil;

import entity.User;

public class Test1 {

    public static void main(String[] args) {
        getAll();
        getOne();
    }

    /**
     * 获取所有
     */
    public static void getAll() {
        Connection conn = DbUtil.getConnect();
        try {
            List<User> list = DbUtil.queryRunner().query( conn, "select * from tp_user", new BeanListHandler<User>(User.class));
            for (User u : list) {
                System.out.println(u.getUsername());
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    /**
     * 获取单个
     * 
     * @return
     */
    public static void getOne() {
        Connection conn = DbUtil.getConnect();
        User u;
        try {
            u = DbUtil.queryRunner().query(conn, "select * from tp_user where id=?", new BeanHandler<User>(User.class), 1);
            System.out.println(u.getUsername());
        } catch (SQLException e) {
            e.printStackTrace();
        }

    }
}

DbUtil.java

package utils;

import java.sql.Connection;
import java.sql.SQLException;

import org.apache.commons.dbutils.QueryRunner;

import com.mchange.v2.c3p0.ComboPooledDataSource;
public class DbUtil {
    private static ComboPooledDataSource dataSource = new ComboPooledDataSource();

    public static Connection getConnect() {
        Connection conn = null;
        if(conn == null) {
            try {
                conn = dataSource.getConnection();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        return conn;
    }
    
    public static QueryRunner queryRunner() {
        return new QueryRunner(dataSource);
    }
}

User.java

package entity;

public class User {
    private int id;
    private String username;
    private String password;
    private String date_entered;
    private int status;
    private String update_entered;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public String getDate_entered() {
        return date_entered;
    }
    public void setDate_entered(String dateEntered) {
        date_entered = dateEntered;
    }
    public int getStatus() {
        return status;
    }
    public void setStatus(int status) {
        this.status = status;
    }
    public String getUpdate_entered() {
        return update_entered;
    }
    public void setUpdate_entered(String updateEntered) {
        update_entered = updateEntered;
    }
    
}